Computer-based images are used in many situations. For example, servers, personal computers and video game consoles all use digital images in one or more applications. In some situations, images are used in animation, such as when a motion picture is produced or a video game is operated. In the former example, it is usually acceptable that image rendering takes a certain amount of time, because the rendering is done in advance of presenting the actual motion picture. In the latter example, by contrast, images must be rendered essentially in real time if the game is to be interactive and provide a realistic experience for the user.
The resolution of an object in a computer-generated image changes as the object becomes smaller. For example, this happens as the object moves away from the viewer in screenspace. This can result in a loss of detail. For example, if the object had been provided with small-scale visual characteristics at the higher resolution (such as with a displacement map), such details can be averaged out or entirely disappear as the object gets smaller.